Discovery that Neutrinos Have Mass Gets Nobel Prize in Physics

Yesterday the French sites searched for Nobel
prize, but nobody seems to care today. Even the
Canadian internet sites are not bragging about a Canadian physicist winning
the award. That is very good news for physics, because the lack of public
interest will allow scientists to work without political and social noise.

The Nobel Prize in Physics 2015 recognises Takaaki Kajita in Japan and Arthur
B. McDonald in Canada, for their key contributions to the experiments which
demonstrated that neutrinos change identities. This metamorphosis requires
that neutrinos have mass. The discovery has changed our understanding of the
innermost workings of matter and can prove crucial to our view of the
universe.

Around the turn of the millennium, Takaaki Kajita presented the discovery that
neutrinos from the atmosphere switch between two identities on their way to
the Super-Kamiokande detector in Japan.

Meanwhile, the research group in Canada led by

Arthur B. McDonald could demonstrate that the neutrinos from the Sun were not
disappearing on their way to Earth. Instead they were captured with a
different identity when arriving to the Sudbury Neutrino Observatory.

A neutrino puzzle that physicists had wrestled with for decades had been
resolved. Compared to theoretical calculations of the number of neutrinos, up
to two thirds of the neutrinos were missing in measurements performed on
Earth. Now, the two experiments discovered that the neutrinos had changed
identities.

The discovery led to the far-reaching conclusion that neutrinos, which for a
long time were considered massless, must have some mass, however small.

For particle physics this was a historic discovery. Its Standard Model of the
innermost workings of matter had been incredibly successful, having resisted
all experimental challenges for more than twenty years. However, as it
requires neutrinos to be massless, the new observations had clearly showed
that the Standard Model cannot be the complete theory of the fundamental
constituents of the universe.

The discovery rewarded with this years Nobel Prize in Physics have yielded
crucial insights into the all but hidden world of neutrinos. After photons,
the particles of light, neutrinos are the most numerous in the entire cosmos.
The Earth is constantly bombarded by them.

Many neutrinos are created in reactions between cosmic radiation and the
Earths atmosphere. Others are produced in nuclear reactions inside the Sun.
Thousands of billions of neutrinos are streaming through our bodies each
second. Hardly anything can stop them passing; neutrinos are natures most
elusive elementary particles.

Now the experiments continue and intense activity is underway worldwide in
order to capture neutrinos and examine their properties. New discoveries about
their deepest secrets are expected to change our current understanding of the
history, structure and future fate of the universe.